Question

我有基于LWJGL的Java应用程序。我通过排列在3 x 3网格中的9个顶点缓冲区渲染地形。当摄像机移过某个边界时，9个缓冲区要么更新要么用一组新的地形替换。这一切都很好，除了当一个新的地形块添加9元素阵列时，我的内存增加大约5MB。仅此一项就是预期的。不期望的是前一个地形块占用的5MB内存没有得到清理。

我已经筋疲力尽了我的谷歌，所以我希望有人可以给我一些帮助。我安装并运行了VisualVM。我不明白的是，Windows在大量地形加载和卸载后使用200MB表示我的应用程序。但VisualVM堆转储仅显示12MB。

用于加载地形的游戏循环没有在“main”的高级线程中运行。谁能指出我正确的方向？我会粘贴一些代码，但它太大了我不知道要粘贴哪个位。

while(Game.running) {

        time = Sys.getTime();
        dt = (double)((time - lastTime))/1000.0;
        lastTime = time;

        GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);

        input.pollInput(cam, dt);
        cam.update(terrain.getTerrainHeight());
        sun.render();
        terrain.updateNew(cam.getPosition());
        terrain.render();
        frameRendering();
        //testTriangle();
        Display.update();
    }

有主循环。问题似乎发生在terrain.updateNew（）函数中。

这是：

public void updateNew(Vector3f playerPos)
{
    _playerPos.x = playerPos.x;
    _playerPos.y = playerPos.y;
    _playerPos.z = playerPos.z;
    int width = TerrainChunk.CHUNK_WIDTH;
    _westernBounds = _chunks[4].getOrigin().x + 0;
    _easternBounds = _chunks[4].getOrigin().x + width - 0;
    _northernBounds = _chunks[4].getOrigin().z + 0;
    _southernBounds = _chunks[4].getOrigin().z + width - 0;

    if(_playerPos.x < _westernBounds && !_needUpdate)
    {
        _needUpdate = true;
        _inWestBounds = true;
    }

    if(_playerPos.x > _easternBounds && !_needUpdate)
    {
        _needUpdate = true;
        _inEastBounds = true;
    }

    if(_playerPos.z < _northernBounds && !_needUpdate)
    {
        _needUpdate = true;
        _inNorthBounds = true;
    }

    if(_playerPos.z > _southernBounds && !_needUpdate)
    {
        _needUpdate = true;
        _inSouthBounds = true;
    }

    if(_needUpdate)
    {
        long key = 0;
        long key1 = 0;
        long key2 = 0;
        int[] coords = new int[2];
        HashMap<Integer, Long> needed = new HashMap<Integer, Long>();

        coords = calculateChunkCoords(0);
        key1 = coords[0];
        key2 = coords[1];
        key = key1 << 32 | key2;
        needed.put(0, key);

        coords = calculateChunkCoords(1);
        key1 = coords[0];
        key2 = coords[1];
        key = key1 << 32 | key2;
        needed.put(1, key);

        coords = calculateChunkCoords(2);
        key1 = coords[0];
        key2 = coords[1];
        key = key1 << 32 | key2;
        needed.put(2, key);

        coords = calculateChunkCoords(3);
        key1 = coords[0];
        key2 = coords[1];
        key = key1 << 32 | key2;
        needed.put(3, key);

        coords = calculateChunkCoords(4);
        key1 = coords[0];
        key2 = coords[1];
        key = key1 << 32 | key2;
        needed.put(4, key);

        coords = calculateChunkCoords(5);
        key1 = coords[0];
        key2 = coords[1];
        key = key1 << 32 | key2;
        needed.put(5, key);

        coords = calculateChunkCoords(6);
        key1 = coords[0];
        key2 = coords[1];
        key = key1 << 32 | key2;
        needed.put(6, key);

        coords = calculateChunkCoords(7);
        key1 = coords[0];
        key2 = coords[1];
        key = key1 << 32 | key2;
        needed.put(7, key);

        coords = calculateChunkCoords(8);
        key1 = coords[0];
        key2 = coords[1];
        key = key1 << 32 | key2;
        needed.put(8, key);

        // copy the chunks we have into a searchable has map
        HashMap<Long, TerrainChunk> have = new HashMap<Long, TerrainChunk>();
        key1 = _chunks[0]._origin[0];
        key2 = _chunks[0]._origin[1];
        key = key1 << 32 | key2;
        have.put(key, new TerrainChunk(_chunks[0], _chunks[0]._color));
        key1 = _chunks[1]._origin[0];
        key2 = _chunks[1]._origin[1];
        key = key1 << 32 | key2;
        have.put(key, new TerrainChunk(_chunks[1], _chunks[1]._color));
        key1 = _chunks[2]._origin[0];
        key2 = _chunks[2]._origin[1];
        key = key1 << 32 | key2;
        have.put(key, new TerrainChunk(_chunks[2], _chunks[2]._color));
        key1 = _chunks[3]._origin[0];
        key2 = _chunks[3]._origin[1];
        key = key1 << 32 | key2;
        have.put(key, new TerrainChunk(_chunks[3], _chunks[3]._color));
        key1 = _chunks[4]._origin[0];
        key2 = _chunks[4]._origin[1];
        key = key1 << 32 | key2;
        have.put(key, new TerrainChunk(_chunks[4], _chunks[4]._color));
        key1 = _chunks[5]._origin[0];
        key2 = _chunks[5]._origin[1];
        key = key1 << 32 | key2;
        have.put(key, new TerrainChunk(_chunks[5], _chunks[5]._color));
        key1 = _chunks[6]._origin[0];
        key2 = _chunks[6]._origin[1];
        key = key1 << 32 | key2;
        have.put(key, new TerrainChunk(_chunks[6], _chunks[6]._color));
        key1 = _chunks[7]._origin[0];
        key2 = _chunks[7]._origin[1];
        key = key1 << 32 | key2;
        have.put(key, new TerrainChunk(_chunks[7], _chunks[7]._color));
        key1 = _chunks[8]._origin[0];
        key2 = _chunks[8]._origin[1];
        key = key1 << 32 | key2;
        have.put(key, new TerrainChunk(_chunks[8], _chunks[8]._color));


        Set<Entry<Integer, Long>> set = needed.entrySet();
        Iterator<Entry<Integer, Long>> i = set.iterator();
        // Garbage cleanup?
        while(i.hasNext())
        {
            Map.Entry<Integer, Long> me = i.next();
            if(have.containsKey(me.getValue()))
            {
                _chunks[me.getKey()] = null;
                _chunks[me.getKey()] = new TerrainChunk(have.get(me.getValue()), getColor(me.getKey()));
            } else {
                _chunks[me.getKey()].destroy();
                _chunks[me.getKey()] = null;
                _chunks[me.getKey()] = new TerrainChunk(calculateChunkCoords(me.getKey()), getColor(me.getKey()), this);
            }
        }
        _needUpdate = false;
        have.clear();
        needed.clear();
        have = null;
        needed = null;
    }
}

这是创建顶点缓冲区的函数：

private boolean createVertexBuffer()
{
    _vboVertexAttribues = ARBVertexBufferObject.glGenBuffersARB();
    _vboVertexIndices = ARBVertexBufferObject.glGenBuffersARB();
    //_vboVertexTexture = ARBVertexBufferObject.glGenBuffersARB();

    ARBVertexBufferObject.glBindBufferARB(
            ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, 
            _vboVertexAttribues
    );

    ARBVertexBufferObject.glBufferDataARB(
            ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, 
            (VERTEX_SIZE * VERTEX_COUNT), 
            ARBVertexBufferObject.GL_STATIC_DRAW_ARB
    );

    ByteBuffer vertextPositionAttributes = ARBVertexBufferObject.glMapBufferARB(
            ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, 
            ARBVertexBufferObject.GL_WRITE_ONLY_ARB, 
            (VERTEX_SIZE * VERTEX_COUNT),
            null
    );

    for(int i = 0; i < VERTEX_COUNT; i++)
    {
        vertextPositionAttributes.putDouble(_vPos[i].x);
        vertextPositionAttributes.putDouble(_vPos[i].y);
        vertextPositionAttributes.putDouble(_vPos[i].z);
        vertextPositionAttributes.putDouble(_vNorm[i].x);
        vertextPositionAttributes.putDouble(_vNorm[i].y);
        vertextPositionAttributes.putDouble(_vNorm[i].z);
        vertextPositionAttributes.putFloat(_color.x);
        vertextPositionAttributes.putFloat(_color.y);
        vertextPositionAttributes.putFloat(_color.z);
        vertextPositionAttributes.putFloat(1.0f);
    }


    vertextPositionAttributes.flip();

    ARBVertexBufferObject.glUnmapBufferARB(ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB);
    ARBVertexBufferObject.glBindBufferARB(ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, 0);    

    vertextPositionAttributes.clear();
    vertextPositionAttributes = null;
    // TEXTURE COORDS
    /*ARBVertexBufferObject.glBindBufferARB(
            ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB,
            _vboVertexTexture
            );

    ARBVertexBufferObject.glBufferDataARB(
            ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB,
            (TEXTURE_SIZE * VERTEX_COUNT),
            ARBVertexBufferObject.GL_STATIC_DRAW_ARB
        );

    ByteBuffer vertexTextureCoords = ARBVertexBufferObject.glMapBufferARB(
            ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB,
            ARBVertexBufferObject.GL_WRITE_ONLY_ARB,
            (TEXTURE_SIZE * VERTEX_COUNT),
            null
        );

    for(int i = 0; i < VERTEX_COUNT; i++)
    {
        vertexTextureCoords.putFloat(_vTex[i].x);
        vertexTextureCoords.putFloat(_vTex[i].y);
    }
    vertexTextureCoords.flip();

    ARBVertexBufferObject.glUnmapBufferARB(ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB);
    ARBVertexBufferObject.glBindBufferARB(ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB, 0);*/


    ARBVertexBufferObject.glBindBufferARB(
            ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB,
            _vboVertexIndices
    );

    ARBVertexBufferObject.glBufferDataARB(
            ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB,
            (INDEX_SIZE * INDEX_COUNT),
            ARBVertexBufferObject.GL_STATIC_DRAW_ARB
    );

    ByteBuffer vertexIndices = ARBVertexBufferObject.glMapBufferARB(
            ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB,
            ARBVertexBufferObject.GL_WRITE_ONLY_ARB,
            (INDEX_SIZE * INDEX_COUNT),
            null
    );

    for(int i = 0; i < _nIndices.length; i++)
    {
        vertexIndices.putInt(_nIndices[i]);
    }

    vertexIndices.flip();

    ARBVertexBufferObject.glUnmapBufferARB(ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB);
    ARBVertexBufferObject.glBindBufferARB(ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB, 0);

    // Cleanup our crap
    _fXs = null;
    _fYs = null;
    _fZs = null;
    _vPos = null;
    _vNorm = null;
    _color = null;
    _nIndices = null;
    _vTex = null;
    vertexIndices.clear();
    vertexIndices = null;
    return true;
}

这是渲染功能： public void render（） {

    GL11.glEnableClientState(GL11.GL_VERTEX_ARRAY);
    GL11.glEnableClientState(GL11.GL_NORMAL_ARRAY);
    GL11.glEnableClientState(GL11.GL_COLOR_ARRAY);
    ARBVertexBufferObject.glBindBufferARB(
            ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB,
            _vboVertexAttribues
    );

    ARBVertexBufferObject.glBindBufferARB(
            ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB,
            _vboVertexIndices
    );

    GL11.glVertexPointer(
            3,
            GL11.GL_DOUBLE,
            VERTEX_SIZE,
            0
    );

    GL11.glNormalPointer(
            GL11.GL_DOUBLE,
            VERTEX_SIZE,
            NORMAL_SIZE
    );

    GL11.glColorPointer(
            4, 
            GL11.GL_FLOAT, 
            VERTEX_SIZE, 
            POSITION_SIZE + NORMAL_SIZE
    );


    GL11.glDrawElements(
            GL11.GL_TRIANGLE_STRIP,
            INDEX_COUNT,
            GL11.GL_UNSIGNED_INT,
            0
    );

    ARBVertexBufferObject.glBindBufferARB(
            ARBVertexBufferObject.GL_ARRAY_BUFFER_ARB,
            0
    );

    ARBVertexBufferObject.glBindBufferARB(
            ARBVertexBufferObject.GL_ELEMENT_ARRAY_BUFFER_ARB,
            0
    );

    GL11.glDisableClientState(GL11.GL_VERTEX_ARRAY);
    GL11.glDisableClientState(GL11.GL_NORMAL_ARRAY);
    GL11.glDisableClientState(GL11.GL_COLOR_ARRAY);
}

提前感谢您的任何帮助或建议。

Answer 1

我认为它可能是Java VM从操作系统分配内存的方式的一个工件，特别是即使堆缩小也不会释放页面，但要保持堆不得不再次增长。

但就代码中的内存泄漏而言，重要的是VisualVM所说的堆大小。如果那是稳定的，那里就没有泄漏。

您还应该考虑Java VM本身使用大量本机库和其他消耗物理或虚拟内存的东西，这为每个Java进程提供了大致恒定的开销。

（This也可能有所帮助。）

Answer 2

泄漏可能发生在底层本机库中。似乎LWJGL绑定到本机C库（OpenGL，OpenAL等），我怀疑有用于显示的临时内存缓冲区从未发布过。这将解释为什么VisualVM只显示12 MB（他正在处理的对象），而Windows显示200 MB（由JVM创建的数据，仍然在GC内部和C库中使用的数据）。

您确定使用的是框架吗？

编辑：

我可能会弄错，因为我不熟悉这个特定的库，但是确实您正在使用本机库进行内存分配\操作。

似乎你做得很好，但我注意到了

ARBBufferObject.glGenBuffersARB

分配你的缓冲区。此方法正在包装C原生，因此直到您调用

ARBBufferObject.glDeleteBuffersARB

或终止此缓冲区将保留在内存中。您应该确定createVertexBuffer()创建的数据的生命周期，调用它的时间，以及当您和GPU都没有完成此操作时删除缓冲区。

我再一次不知道OpenGl的这一面，所以有可能更有可能帮助你。您注意到API of ARBBufferObject与C++ Wiki

中讨论的相同

Answer 3

答案很简单：将顶点放在“vertextPositionAttributes”中的缓冲区很可能是一个直接缓冲区，这意味着它存在于GC控制堆之外，并且不可见于JVisualVM。

难以捉摸的Java内存泄漏

3 个答案: